It is often beneficial to provide coatings onto substrates, such that the surfaces of such substrates have desired properties or effects.
For example, it is useful to coat biomedical implants to provide for the localized delivery of pharmaceutical or biological agents to target specific locations within the body, for therapeutic or prophylactic benefit. One area of particular interest is drug eluting stents (DES) that has recently been reviewed by Ong and Serruys in Nat. Clin. Pract. Cardiovasc. Med., (December 2005), Vol 2, No 12, 647. Typically such pharmaceutical or biological agents are co-deposited with a polymer. Such localized delivery of these agents avoids the problems of systemic administration, which may be accompanied by unwanted effects on other parts of the body, or because administration to the afflicted body part requires a high concentration of pharmaceutical or biological agent that may not be achievable by systemic administration. The coating may provide for controlled release, including long-term or sustained release, of a pharmaceutical or biological agent. Additionally, biomedical implants may be coated with materials to provide beneficial surface properties, such as enhanced biocompatibility or lubriciousness.
Conventional solvent-based spray coating processes are hampered by inefficiencies related to collection of the coating constituents onto the substrate and the consistency of the final coating. As the size of the substrate decreases, and as the mechanical complexity increases, it grows increasingly difficult to uniformly coat all surfaces of a substrate.
A cost-effective method for depositing inert polymers and pharmaceutical or biological agents onto a substrate, where the collection process is efficient, the coating produced is conformal, substantially defect-free and uniform, the composition of the coating can be regulated and the morphology and/or secondary structure of the pharmaceutical or biological agents can be controlled is described in PCT/US 06/027,321, incorporated herein by reference in its entirety. The method permits structural and morphological preservation of the agents deposited during the coating process. The method as described in PCT/U.S. 06/027,321 contemplates electrically charging the stent and creating an electrical field around the stent and stent holder during the coating method.
What is needed, therefore, is a stent holder which mounts and electrically charges a stent.